SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3486b04d5cbb3538b7d4e8bf7d4702d9ee914f3d32b14db42daeb2fa3a27668' 
  AND token = 'PsnxfYidD5qfMdLtakSMCAGzpZW7awApBLaY/eFjK14=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}